A method of manufacturing a molding by compressing and solidifying molding material, a representative of which is powder granule etc., is generally used in a wide range of industry including, for example, not only industrial fields of pharmaceuticals and foods (functional foods and general foods) but also electronic material fields such as molding of semiconductor encapsulating resin, battery-related products, powder metallurgy-related products, electronic functional parts and the like, and fields of agricultural chemicals and sanitary products.
In the field of pharmaceuticals, among formulations for oral administration in particular, a solid molding called “tablet” is presently one of the most widely used form of medicines in view of various merits including simplicity and convenience in manufacturing and easiness of oral administration. Among such moldings, the molding having an internal core is called “tablet with a core” since such a molding is manufactured by compression-molding powder granule placed around a core (center tablet) to form an outer layer.
Such a molding with a core as a dry coated tablet was conventionally manufactured by a method comprising: preparing a core as a molding by another tablet machine previously; supplying the core as a molding into a die of a dry coated tablet machine fed and filled with powder granule for an outer layer; and further supplying and compression-molding the powder granule for the outer layer. This manufacturing method involves serious problems of an increased amount of operation and a lowered production efficiency as compared with a method of manufacturing an general compression molding. Further, the method involves problems associated with feeding of cores, such as an occurrence of a tablet with no core, multiple cores, or off-centered core and hence requires a complicated mechanism or apparatus for monitoring core feeding and checking final molded products to assure the quality of each product, thus resulting in the machine or equipment increased in size and complicated in structure.
In view of such circumstances, the inventors of the present invention invented a method of manufacturing a molding with a core efficiently from such a molding material as powder granule at a time, as described in patent document 1. This method uses compression molding means having a die and an upper and a lower punches, of which at least the upper punch, preferably both of the upper and lower punches have a double structure comprising a center punch and an outer punch surrounding the outer periphery of the center punch, both of the center punch and the outer punch being slidable and capable of a compressing operation. This manufacturing method comprises: the steps of supplying molding material for the core and molding material for the outer layer respectively; the step of compression-molding the molding material for the core and/or the molding material for the outer layer; and the step of compression-molding the whole molding with a core.
Further, the inventors of the present invention invented a rotary compression molding machine described in patent document 2 as an apparatus for practicing the aforementioned method of manufacturing a molding with a core.
A specific example of such a method of manufacturing a molding with a core by using upper and lower punches both having such a double structure comprises: an outer layer supply step 1 of supplying molding material for the outer layer into a space defined above a lower center punch and enclosed by a lower outer punch; a core supply step of supplying molding material for the core into a space defined above the molding material for the outer layer supplied in the preceding step and enclosed by the lower outer punch; an outer layer and core molding step of compression-molding the molding material for the outer layer and the molding material for the core supplied in the preceding steps; an outer layer supply step 2 of supplying the molding material for the outer layer into a space defined above and around the outer layer and core molding in the die molded in the preceding step; and a whole molding step of compression-molding the outer layer and core molding and the molding material for the outer layer.
Patent Document 1: International Laid-Open Publication No. WO 01/98067 pamphlet
Patent Document 2: International Laid-Open Publication No. WO 02/90098 pamphlet